Concentrations of the fungicide azoxystrobin and the insecticide thiamethoxam on sugarcane seed billets following chemical treatment

Authors: White, Paul; WAYMENT, DARCEY - Nicholls State University; MAYON, NICHOLAS - Nicholls State University

Submitted to: American Society of Sugar Cane Technologists
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/14/2020
Publication Date: 12/15/2020
Citation: White Jr, P.M., Wayment, D.G., Mayon, N. 2020. Concentrations of the fungicide azoxystrobin and the insecticide thiamethoxam on sugarcane seed billets following chemical treatment. Journal of the American Society of Sugar Cane Technologists. 40:36-45.

Interpretive Summary: Sugarcane (Saccharum spp.) is typically planted using whole stalk seed in Louisiana. However, mechanically planting short stalk pieces, or billets, is increasingly being used by growers when whole stalk seed is lodged or when labor is scarce. Thus, improved planting methods for billets are needed. Recent research indicates that treating the billets prior to planting with fungicides and/or insecticides can increase cane yields. However, the amount of chemical remaining on the billets following treatment is not known. Agriculture chemicals can only be applied at certain rates to limit the chance for off-site impacts to human health and the surrounding environment. Therefore, this research was conducted to measure the amount of fungicide and insecticide remaining on billets following chemical treatment. Four laboratory experiments were conducted using the commercial sugarcane cultivar ‘L 01-299’. The rate of azoxystrobin applied represents about 6.4% of the annual rate limit for the fungicide, and 40% of the annual label rate for the insecticide. These treatment rates were found to give consistent increases in stalk number and cane yield, when compared to untreated billet seed, in field experiments. Thus, treating billets before planting uses less agricultural chemicals and achieves increased sugarcane yields.

Technical Abstract: Sugarcane (Saccharum spp.) is typically planted using whole stalk seed in Louisiana. However, cultural practices for improving billet planting success by reducing risk are needed. Pre-plant seed treatment of billets shows promise when combined with the appropriate chemistry. Recent research suggests fungicides and insecticides may be the optimal choices for chemical seed treating billets. Therefore, this research was conducted to quantify the amount of azoxystrobin and thiamethoxam remaining on billets following chemical treatment. Four laboratory experiments were conducted using the cultivar ‘L 01-299’. Results demonstrated that dip-treated billet seed contained on average 10.6 mg azoxystrobin or 17.3 mg thiamethoxam kg-1 billet wet wt. when applied as single solutions containing either Quadris® or Platinum® 75 SG, respectively. A solution containing both Quadris and Platinum deposited 9.7 mg azoxystrobin and 15.7 mg thiamethoxam kg-1 billet wet wt., respectively. At a billet seeding rate of 5.4 Mg ha-1 this pesticide application corresponds to 0.057 kg ha-1 and 0.094 kg ha-1 of azoxystrobin and thiamethoxam, respectively. The rate of azoxystrobin represents about 6.4% of the annual label rate for Quadris, and 40% of the annual label rate for a product with the same active ingredient, thiamethoxam, as Platinum. These treatment rates were found to give consistent increases in stalk number and cane yield, when compared to untreated billet seed, in field experiments.